Basal Cell Carcinoma



Basal Cell Carcinoma


David Cassarino, MD, PhD










Clinical photograph of a large facial BCC shows areas of ulceration and granulation-like tissue surrounded by a raised border image. (Courtesy S. Yashar, MD.)






High magnification of a nodular BCC shows a sheet-like proliferation of atypical basaloid cells with high N:C ratios and numerous apoptotic image and mitotic figures image.


TERMINOLOGY


Abbreviations



  • Basal cell carcinoma (BCC)


Synonyms



  • Basal cell epithelioma (BCE)


  • Trichoblastic carcinoma (not well accepted and should be discouraged)


Definitions



  • Low-grade malignancy of basaloid-appearing keratinocytes


ETIOLOGY/PATHOGENESIS


Multifactorial



  • Related to sun exposure (vast majority of cases)



    • Some cases may also be associated with radiation, immunosuppression (organ transplantation), burn scars



      • These cases tend to be more aggressive


  • May actually be derived from follicular stem cells (hence, “trichoblastic carcinoma”)


Genetics



  • Rare cases are associated with genetic syndromes including nevoid basal cell carcinoma (Gorlin) syndrome, xeroderma pigmentosum, basex syndrome, Rombo syndrome, and McKusick syndrome



    • Genes implicated include PTCH1 (Gorlin syndrome), P53, SOX9, BMI1, BAX, RMRP


CLINICAL ISSUES


Epidemiology



  • Incidence



    • Extremely common: Most common cancer in humans when skin cancers are included



      • Accounts for 70% of primary cutaneous malignancies


  • Age



    • Typically older adults; few cases in young adults



      • If in a child, should consider a genetic syndrome


  • Gender



    • Slightly greater incidence in males


  • Ethnicity



    • Caucasian/light-skinned individuals


    • Rare in darker skin types


Site



  • Most common in head and neck region (up to 80% of cases)



    • About 15% occur on trunk and shoulders


    • Very rare cases involve lips, breast, axillae, groin, inguinal region, and genitalia


Presentation



  • Typically papular, plaque-like, or nodular lesion



    • Often present as a pearly, translucent papule with telangiectasia


    • Larger lesions often ulcerated with bleeding &/or overlying crusting


    • Minority of cases are pigmented, more often in Asians and Africans


Treatment



  • Surgical approaches



    • Complete excision or electrodessication and curettage (ED&C)


    • Mohs micrographic surgery often used in facial cases


Prognosis



  • Usually excellent, cured by local excision


  • More aggressive subtypes, including micronodular, infiltrative, desmoplastic, and basosquamous, have higher rate of recurrence and increased risk of metastasis



    • Overall risk of metastasis estimated at 0.05%



MACROSCOPIC FEATURES


Size



  • Variable, small (few mm) to large (several cm)


MICROSCOPIC PATHOLOGY


Histologic Features



  • Tumor is composed of nodules, nests, &/or infiltrative cords



    • Overlying ulceration and serum crusting often present in large tumors


  • Proliferation of small basaloid cells with peripheral palisading


  • Stromal retraction artifact



    • Between tumor cells and stroma


  • Mucinous material may be present


  • Numerous mitotic and apoptotic figures present


  • Cells show enlarged hyperchromatic nuclei with inconspicuous or small nucleoli and scant eosinophilic cytoplasm


Variants



  • Superficial-multicentric: Superficial nests attached to epidermis separated by areas of uninvolved epidermis


  • Nodular: Large, rounded predominantly dermal-based nests with prominent peripheral palisading


  • Micronodular: Predominantly dermal-based infiltrative proliferation of small nests


  • Infiltrative: Small cords and nests, often deeply invasive


  • Desmoplastic/sclerosing/morpheaform: Infiltrative strands and nests associated with dense sclerotic stroma


  • Infundibulocystic: Mature folliculocystic spaces containing keratinous material


  • Basosquamous/metatypical: Prominent areas of squamous differentiation (may mimic squamous cell carcinoma [SCC]), less peripheral palisading present


  • Fibroepithelioma of Pinkus: Numerous small, anastomosing cords of basaloid cells attached to the epidermis


  • Rare variants include adenoid, clear cell, signet ring cell, plasmacytoid/myoepithelial, and BCC with neuroendocrine differentiation

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Jul 8, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Basal Cell Carcinoma

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